Lisa built a rectangular flower garden that is $4$ meters wide and has a perimeter of $26$ meters. What is the length of Lisa's flower garden?
Explanation: Perimeter is the distance around a closed figure. We can find the perimeter of a shape by adding all the side lengths. The perimeter is $26}\text{ m}$ and the width is ${4}\text{ m}$. $\text{Perimeter}= 26\text{ meters}\,$ $\,4\text{ m}$ $\,4\text{ m}$ $\begin{aligned} P} &= {l} + {w} + {l} + {w}\\\\ 26} &= {\ell} + 4 + {\ell} + 4 \\\\ 26} &= {\ell} + {\ell} + {8}\\\\ 18&= {\ell} + {\ell} \end{aligned}$ What number can we add twice to get $18$ ? The length of the flower garden is ${9}$ meters.